The present invention relates to field emitters, particularly gated field emitters for flat panel displays and vacuum microelectrics, and more particularly to electrochemical sharpening of field emission tips.
Flat panel displays and vacuum microelectronics utilize gated field emitters, and it is very important to initiate electron emission at the lowest possible voltage. Both the materials of the emitter and the gate, as well as the geometry of the emitter-gate structure, are very important in this regard. By forming an extremely sharp (needle-like) emitter tip and a correctly configured grid (gate) hole in which the emitter resides, emission is more uniform among the emitters and the turn-on voltage, which initiates electron emission, is lowered. Thus, there is a need for forming field emitters with sharp tips or for sharpening tips of previously formed field emitters.
The present invention is directed to sharpening of previously formed field emitter (nanofilament type) tips, wherein tip sharpening is carried out by electroetching/polishing using the grid (gate) of the field emission structure, such as a field emission triode structure, as a counter electrode. Electroetching performed in this way can produce extremely sharp emitter tips as well as removing asperities and other imperfections in the emitters, each in relation to the specific grid (gate) hole in which it resides.